Microbial contamination is a primary cause of disease. Bacteria and viruses can be found in water, on food and on surfaces. Currently, there are several different technologies available to eliminate these contaminants from drinking water. However, the effectiveness of a particular method depends on the influent water and the type of microbe present.
Increased concern from the public on issues of water quality has resulted in an explosion of water filtration devices on the market, particularly for household use. A popular household water filtration device is in the style of a pour-through pitcher. Typically, unfiltered water is added to a basin at the top of the device. Through the action of gravity, water percolates through a filtering media (usually consisting of granulated activated carbon) located between the basin and a collection reservoir. Filtered water is then dispensed from the collection reservoir for drinking. For the general public, gravity-controlled pitcher-type water filtration systems are cost effective. Many such water filtration systems are provided under the Brita® brand name.
One limitation of this kind of device is the inability to filter out and destroy smaller organisms and microbes. To facilitate the flow of water, the filtering media through which water is drawn needs to be of a porous nature. Because of this necessity, such devices do not filter as effectively as other water treatment devices. Part of this inefficiency is caused by a lack of additional purification steps currently available in the prior art, such as ozonation, ultra-violet irradiation, and cell membrane electrofragmentation.
The filtering media or cartridge used in these pitcher-type filtering systems usually extends down into the collection reservoir, coming in contact with the filtered water. The porosity of the filter media promotes the infiltration, collection and growth of organisms. Thus, there is an increased potential for contamination of the filtered water.
The lack of additional purification steps limits the use of the filtered water produced by such prior art devices to drinking water purposes, as opposed to other potential applications for the use of purified or treated water.
U.S. Pat. No. 5,225,078 issued to Polasky et al., discloses a pour-through gravity-flow pitcher filter.
U.S. Pat. No. 6,103,114 issued to Tanner et. al., cites a device which attempts to avoid cross contamination by the design of the spout, pour area and seal between the inner reservoir and the filtered water reservoir. However, the filter in this design still extends into the filtered water reservoir and is a potential source of contamination.
U.S. Pat. No. 6,391,191 issued to Conrad discloses a domestic water treatment appliance with a pump which uses ozone and a carbon block filter to disinfect water, but does not utilize a pour-through filter prior to the ozonation process.
U.S. Pat. No. 6,238,552 issued to Shannon discloses a universal insert for a water purifier with filter on top and bottom and a guide for sliding into a pitcher.
U.S. Pat. Nos. 4,969,996 and 4,306,971 issued to Hankammer discloses a column-like filter device extending into collection reservoir and, thus, yields a potential source of contamination.
U.S. Pat. No. 6,290,848 issued to Tanner et al., discloses a porous particulate filter for removing 99.95% of all 3-4 μm cryptosporidium and other protozoan cysts. U.S. Pat. No. 6,103,114, also issued to Tanner et al., describes a carafe-style filter device with lip over the edge to prevent untreated water from mixing with treated water when pouring.
U.S. Pat. No. 6,405,875 issued to Cutler discloses a carafe-style filter device with an ion-exchange resin and carbon granules which removes 99.95% of all 3-4 μm particles. However, this device extends into filtered water reservoir and thus may be susceptible to contamination.
Thus, there is a need for a water filtration device that keeps the filtering media from being in contact with the filtered water. There is also a need for an effective drinking water filtration and purification system which takes advantage of different treatment methods. There is a further need for a purification or sanitization system and/or method that can be used to sanitize different items, while taking advantage of improved purification techniques.